Drilling machine



Aug. 18, 1942. E. J. HIRVONEN DRILLING MACHINE '7 Sheets-Sheet .1

Filed July 30, 1940 18, 1942- E. J. HIRVONEN Y 2,293,464

DRILLING MACHINE Filed July 30, 1940 7 Sheets-Sheet 2 w 60 Fig.2. 62

Aug. 18, 1942. E, J. HIRVQNEN $293,464.

DRILLING MACHINE Filed July 30, 1940 7 Sheets-Sheet 3 530 596 .598 600 5 a ITIUBFI?'OTZ 1942- E. J. HIRVONEN 2,293,464

DRILLING MACHINE Filed July 30, 1940 7 Sheets-Sheet 4 1942- E. J. HIRVONEN 2,293,464

DRILLING MACHINE Filed J l :50, 1940 'r Sheets-Sheet 5 w w & 4

6 w m y r 2 V N. 4 m a mm: ifiw msiw a i n.

I 1 e v T E. .1. HIRVONEN DRILLING MACHINE 7 Sheets-Sheet 6 FileC 1 July 50, 1940 'HIIH Aug. 18, 1942. E. J. HIRVONEN DRILLING MACHINE Filed July 30, 1940 7 Sheets-Sheet 7 Ewan"- fnve rlior. Gukd- W NAW NR, Em Q Patented Aug. 18, 1942 UNlTED STATES PATENT 'iFFlCE DRILLING MACHINE Application July 30, 1940, Serial No. 348,389

49 (llaims.

This invention relates to a hydraulic drilling machine having provision for automatic, as well as manual, control of the rate and direction of relative movement between the drill and the work.

In the present machine, herein shown as a ate automatically in dilTerent ways or cycles, in-

eluding complete manual control of the speed, direction of movement and position, as determined by the setting of suitable cycle selecting valve mechanism.

The hydraulically operated drilling machine of the present invention is so arranged that it can be operated like an entirely mechanical hand operated sensitive drilling machine, where the direction and rate of movement of the work supporting table and the pressure of the drill on the work is controlled by a suitable hand lever, the work following the movement of the hand lever at a proportional speed and exerting pressure on the drill in proportion to the manual pressure on the hand lever.

The machine is also arranged to operate on several cycles as follows:

A. A fast approach from a neutral or retracted position to a stop position close to the drill in response to the depression of a foot pedal, and then a slow feed against the drill upon release of the pedal and an automatic retraction from the drill after the full depth of hole has been drilled. Depression of the pedal during any advanced position of the Work eliects the automatic retraction of the work to the neutral or retracted position.

B. An automatic cycle consisting of a fast approach to the drill, a slow feed against the drill without any stop at the end of the fast approach stroke, and a rapid retraction to the neutral if position, the cycle being initiated by the depression of the foot pedal and the movement being reversed at any intermediate advanced position of the work by a subsequent depression of the pedal.

C. A continuous repetition of the automatic cycle consisting of a rapid advance to the drill, a slow feed against the drill, a rapid traverse to a position clearing the drill, and a repetition of the aforesaid initiated by depressing the pedal and continued by holding the pedal depressed, emergency return being effected by the release, the depression and subsequent release of the pedal.

D. Purely hand feed.

The various cycles are selected and are caused to be rendered operative by appropriate cycle see lecting valve mechanism. A machine thus ar-. ranged constitutes a further object of the present invention.

Another object of the invention is generally to improve the operation of hydraulic drilling machines.

This application is a continuation in part of my application Serial No. 237,510, filed October 28, 1938, wherein is shown and claimed a hydraulic drilling machine arranged for purely manual control of the speed and direction of movement of the drill and pressure of the drill on the work.

Fig. 1 is a side elevation of a hydraulic drilling machine and hydraulic fluid supply unit embodying the present invention.

2 is a plan view of several of the drilling machine units of Fig. 1, arranged in line, and taking hydraulic fluid from a common supply.

Fig. 3 is a side elevation of the table reciprocating hydraulic cylinder and piston and control mechanism of Fig. 1, part of the movable work supporting table being broken away.

Fig. 4 is a front elevation of the mechanism of Fig. 3.

Fig. 5 is a plan view of the mechanism of Fig. 3 taken along line 55 of Fig. 4.

Fig. 6 is a side elevation of the hydraulic cylinder.

Fig. 7 is a plan view of the cylinder.

Fig. 8 is a sectional detail taken along line 8-8 of Fig. '7, and illustrating particularly the arrangement of oil passages.

Fig. 9 is an enlarged sectional detail of the manual control valve and its associated mechanism, taken along lines 99 of Figs. 4 and 10.

Fig. 10 is a section taken along line Ill-l0 of Fig. 9.

Fig. 11 is an enlarged sectional detail of the lower end part of the manual control valve taken at right angles to the section of Fig. 9.

Fig. 12 is a sectional detail taken along line Iii-42 of Fig. 11.

Fig. 13 is a section taken along line l3-|3 of Fig. 9, and illustrating particularly the hydraulically-operated valve holding and setting plungers.

Fig. 14 is a section through the feed-rate controlling valve, taken along line I i-I l of Fig. 4, the valve being illustrated in an open position thereof.

Fig. 14a is a sectional detail of the manual valve setting lever of Fig. 14, taken along line Ida-44a of Fig. 4.

Fig. 14b is a detail illustrating the arrangement of the exhaust oil port of the feed-rate valve, viewed from the left hand end of the feed- -rate valve block of Fig. 14.

Fig. 15 is a sectional view taken along line II5 of Fig. 4, and illustrating particularly the governing valve for securing an unvarying rate of movement of the table regardless of pressure variations between the work and the drill.

Fig. 16 is a plan view of the valve block assembly of Figs. 3 and 4, containing the cycle selecting valves, the selector controlled switching valves and the work-position-controlled reversing valve.

Fig. 17 is an end view of the valve block assembly of Fig. 16.

Fig. 18 is a sectional detail taken along line I8--I8 of Fig. 16, and illustrating the switching valves.

Fig. 19 is a sectional view taken along line I9I9 of Fig. 16, and illustrating the reversing valve.

Fig. 20 is a section through the cycle selector valve block taken along line 2020 of Fig. 16.

Fig. 21 is a section taken along line 2I-2I of Fig. 16.

Fig. 22 is a section taken along line 22-22 of Fig. 16.

Fig. 23 is a side elevation of the cycle selecting valve.

Figs. 24, 25 and 26 are sections taken along lines 24-24, 2525, and 2626, respectively, of Fig. 23, and corresponding with Figs. 20, 21 and 22, respectively, which sections are hereinafter termed the X, Y and Z sections of the selector valve.

Fig. 27 is a side elevation of the selector valve with the valve in a partially rotated position with respect to the position illustrated in Fig. 23 to show an internal port-interconnecting passage.

Fig. 27a is a plan lay-out of the passages of the cycle selector valve of Fig. 23.

Fig. 28 is a side elevation of the hydraulic cylinder, table, valve mechanism and supporting column with the side web of the table broken away to illustrate the valve mechanism and the cam mechanism carried by the column for controlling the reversing valve to control the beginning of the slow feed advance and the amount of feed advance and retraction of the table.

Fig. 29 is an end view of the cam operated reversing valve controlling mechanism of the cylinder and table, looking up in Fig. 28.

Fig. 30 is a plan view of the cam operated to the left in Fig. 28.

Fig. 31 is a diagram of the hydraulic circuits of the apparatus, with the selector valve set for the performance of cycle A.

Figs. 31a, 31b and 310 are respectively fast,

advance, feed and retraction positions of the reversing valve controlling mechanism, looking",

the upper part thereof a housing 44 which .sup-

ports a plurality of drill spindles 46 that are adjustable as to their position with respect to each other and are driven by an electric motor 48 common to all spindles. The column under the drill spindle is provided with vertical ways 56 on which a work supporting table 52 is vertically movable by hydraulic mechanism including a vertical hydraulic cylinder 54 disposed under and fixed to the table and a piston 56, Fig. 4, operative within the cylinder and fixed to the upper end of a vertical piston rod 58 bolted to the base 42. As thus arranged, the piston and piston rod are fixed and remain stationary and the cylinder and table reciprocate.

The cylinder receives oil under pressure through control mechanism, later to be described, from a constant pressure oil supply comprising a gear pump 68 driven by a constant speed motor 62, the pump and motor being mounted on the cover of an oil tank 6- 5. unit is intended to maintain an ample supply of oil under constant pressure at all times when operating. The particular unit herein employed is now well known in the art and is illustrated in my joint patent with Benjamin S. T. Bishop No. 1,905,133, issued April 25, 1933.

Oil under pressure is delivered from the supply unit into a pressure manifold 66 to a battery of similar hydraulic drilling machines and exhaust oil from the machines is delivered to a manifold 68 from whence the oil returns into the tank. The high pressure and exhaust oil manifolds are connected to a junction box III associated with each machine Where the high pressure and the exhaust oil pass through flexible pipes or hose I2 and I4, respectively, between the junction box to the valve mechanism carried by and movable with the table.

The hydraulic cylinder 54, see especially Figs. 6, 7 and 8, is provided intermediate its ends with a pad I6 to the face of which a feed-rate controlling valve block I8 is bolted. The cylinder has upper and lower oil passages or ducts and 82, respectively, which open into the face of the pad and register with appropriate passages in the valve block. The upper and lower ends of the ducts open into the upper and lower ends of the cylinder, as illustrated in Fig. 8 respectively above and below the piston at its extreme positions.

The valve block I8 has a high pressure oil passage 84 therein which has one opening in the lower face of the block where it connects with the high pressure hose or flexible conduit I2 and has another opening in the right hand side face of the block where it communicates with a handcontrolled valve casing 66. The valve block I8, see Figs. 4, 14, 15 and 31, contains a speed or feed-rate setting valve 88 by which the cutting speed of the table is set and a governing valve 90 which maintains the cutting speed uniform regardless of variations in pressure between the drill and the work at any speed as set by the speed setting valve 88.

The speed setting valve 88 is of the piston type and includes two spaced pistons 92 and 94, Fig. 14, operating in a vertical passage or cylinder 96, the ends of the passage being closed by screws 98 and I66. A spring I62 acts endwise on the lower end of the valve to press the upper end against an eccentric part H64 of a shaft I06 journalled horizontally in the valve block and extended through the cover I68 thereof and having a manually-engageable arm H6 fixed to the outer end thereof. The free end of said arm The pressure supply has an indicating projection H2 which travels over an arcuate speed indicating scale II 4 carried by the cover plate. The arm Hi) can be clamped in any adjusted position by means of a bolt II6 which passes through the end of the arm and is free for axial movement therein but is held against rotation. The inner end part of the bolt operates in an arcuate slot II8 of the cover plate and has a head which overlies the slot. Thus by tightening up the finger grip member I28, which is screw-threaded on the bolt, the arm can be clamped to the cover plate in any set position. It will be apparent that the swinging of the arm causes the eccentric part I84 of the shaft I86 to rise and fall and thereby varies the vertical position of the feed-rate set ting valve 83.

The valve cylinder 98 is provided with a port I22 which opens into the high pressure duct 84 so that pressure oil is always maintained between the valve pistons 88, 98. The upper valve piston 88 controls the flow of high pressure oil from the valve cylinder 93 through the port I26 by cutting off more or less of the area of the port as determined by the setting of the valve under control of the shaft I88, or by completely closing said port by hydraulic operation as will be explained hereinafter. The port I25 is in line with and communicates with the port I26 in the valve cylinder I28 or" the governing valve 88 from whence oil ultimately flows into the top of the cylinder 54 through an upper port I30 and a duct I32, see also Fig. 31. The lower valve piston 94 of the feed regulating valve is arranged to control the effective opening of a lower duct I34 which receives exhaust oil from the bottom end of the cylindenthe oil coming from a duct I35 and passing, as throttled by the valve, out of the valve cylinder through a lower port I38 into an exhaust duct Hi] and thence to drain. The outlet duct I3=i is provided with a small notch I42, see Figs. 14, 14b, in its lower wall so that when the lower valve piston 94 moves downwardly to close the port ISt either by manual operation of the arm H8 or by hydraulic operation, the outflow of oil from the bottom of the cylinder is not suddenly stopped but is throttled in a more or less gradual manner.

The feed valve can be moved downwardly in dependently of direct manual control by the introduction of pressure oil into the cylinder chamber IM above the top piston 88 through a duct I46 under control of the cycle selecting valve apparatus hereinafter to be described.

The speed governing valve 98 has two valve pistons I48 and I58 operating in the valve cylinder I28, the cylinder being closed at the top and bottom ends by screws I52, I54, respectively. A compression spring I56 is in the cylinder and bears against the lower end of the valve to maintain it normally in raised position against the upper screw I52. The incoming oil, flowing at a rate determined by the setting of the feed valve 88, enters the valve cylinder I28 through the port I26 and passes out of the cylinder through the upper port I30 and through the duct I32 into the top of the cylinder, as has been described. Oil is introduced into the upper cylinder chamber I58 through a duct I60, see Fig. 31, communicating with the duct I36 so that the back pressure oil in the bottom of the cylinder influences the setting of the governing valve 90 to cause the governing valve to increase the throttling efiect on the inflowing oil in accordance with the increase of back pressure of the outfiowing oil. 7

With the arrangement of the speed setting and governing valves, the movement of the table is uniform for any setting of the speed valve regardless of variations in pressure between the work and the drill. The fundamental principle of operation of these valves is not herein novel as it is described, for instance, in my Patent No. 2,073,518, dated March 9, 1937, although the manner of the manual setting of the speed valve is herein novel. The lower end of the governing valve cylinder I28 is connected to the exhaust duct I48 through a restricted passage I62 which serves to prevent sudden movements of the valve.

The speed setting and governing valves are operative for parts of the automatic cycles when the machine is set for automatic operation but are rendered inoperative when the machine is set for entirely manual operation, as will presently appear.

The control of the oil flow into and out of the upper and lower ends of the hydraulic cylinder is also under control of main or master valve mechanism located within the valve block 86, this mechanism being susceptible of purely manual operation and also being susceptible of hydraulic control. Said valve mechanism, see especially Figs. 9, 10, 11, 12 and 31, includes a valve cylinder I84 having upper, intermediate and lower annular ports I56, I88 and Ill], respectively, which communicate through upper, intermediate and lower ducts II2, I'M, I16, respectively, with the ducts I32, 84 and I38, respectively, of the valve block I8. Thus the intermediate port I88 is constantly under high pressure oil from the oil supply and the upper port IE6 is in constant communication with the upper end of the cylinder and the lower port H8 is in constant communication with the lower end of the cylinder. The valve cylinder also has a lowermost port II8 which communicates through a duct I with the exhaust duct I48 of the valve block I8, by which duct the exhaust oil from the speed and governing valves passes to the drain. The bottom end of the valve cylinder is closed by a plug I82 through the bottom of which the drain hole I4 communicates.

The valve cylinder I64 has a valve sleeve I84 fixed therein provided with upper, intermediate and lower ports I88, I88 and I98, which register with respective ports I86, I88 and Ill). The valve sleeve is clamped in place by a disc I82 which is screw-threaded into the lower end of the valve cylinder and presses the sleeve against a spacing ring I94 seated on a shoulder in the upper end of the cylinder.

A hollow valve I86 reciprocates vertically within the sleeve and has upper and lower lands I98 and 289, respectively, which normally confront and seal the ports I and I of the valve sleeve. The valve also has end lands 282 and 284 which provide exhaust passages between them and the adjacent lands I98, 288, which passages open to the interior of the valve. Thus upward displacement of the valve opens the port I 85 to receive high pressure oil from the intermediate port I88 t e ect the upward movement or" the work supporting table. At the same time. the valve opens the lower port H28 to discharge oil from the bottom of the cylinder into the interior of the valve where the oil runs into the drain M. Depression of the valve from the mid position causes high pressure oil to be admitted into the lower end of the cylinder to retract the work supporting table and causes exhaust oil to flow to waste from the upper end of the cylinder. When the valve cylinder is in a partial port open position the flow of oil through the ports is partially restricted resulting in a reduced rate of movement of the table.

The valve is held in mid position by a series of short compression springs 206 which bear between the threaded ring I92 and a disc 208 which overlies the lower end of the valve and is seated thereon and also normally on the valve sleeve. Similar compression springs 2 II] are located. above the valve and bear against a disc 2I2 screwthreaded into the upper end of the cylinder and a floating disc 2l4 normally seated on the upper end of the valve and the upper end of the valve sleeve. With this arrangement, the valve is normally held in the mid position illustrated and movement of the valve in either direction is resisted by one or the other set of springs. The springs are preferably short so that they offer increased resistance to increased displacement of the valve.

The valve is provided with an axially located valve stem 216 which extends through the disc 2| 2 and has an annularly grooved collar 2| 8 at its upper end in the grooves of which are located pins or" an arm 22!] which outstands from a hub 222. The hub is carried at the ends of a pair of parallel arms 224, the other ends of which are connected integrally through a sleeve 226 journalled freely by anti-friction bearings on a stud 228 fixed in the valve housing 86. The arm 22!), hub 222 and arms 224 constitute a lever for operating the valve. Thus vertical movement of the lever about the shaft 228 causes corresponding movement of the valve I96.

Th movements of the valve are controlled hydraulically and also independently manually. The manual control of the setting of the valve includes a shaft 230 journalled freely by antifriction bearings in the hub 222 and projecting loosely through the front cover plat 232 of the valve housing. The projecting end of the shaft is fixed to the end of a control handle 234 projecting forwardly under the table and terminating in a knob 236. Thus by raising and lowering the handle the shaft 230 is rotated in pposite directions.

The inner end of the shaft passes through and is fixed in the hub 240 of a gear sector 242, the teeth of which mesh with the teeth of a vertical rack 2M slidable through the housing 86. The rack passes through the housing and the lower end part thereof is located within a standard 246, see Fig, 1, fixed to the base 42 of the pedestal. The rack is slidable in the standard 2145 or it can be clamped immovably with respect thereto by means including the clamping lever 248. For automatic operation of the machine the rack is free from the standard and can reciprocate with the table relatively thereto. For purely manual operation of the machine the rack is clamped to the standard so that the valve housing 86 reciprocates relatively thereto.

Bearing in mind that the feed-rate and governing valve are not operated when the device is arranged for purely manual operation, either by the setting of the cycle selecting valve pres ently to be described, or by the setting of the feed valve in closed position, the manual operation is essentially as follows:

With no pressure on the operating handle 234, the valve E56 is maintained in closed position by the upper and lower sets of springs and hence ducts leading from th top and bottom ends of the cylinder will be closed and the table thus is locked hydraulically in position. If now the handle 234 is raised upwardly the gear sector 242 is caused to pivot on the fixed rack 254 and hence the lever system associated with the valve is raised, thereby raising the valve and letting high pressure oil flow into the upper end of the cylinder and allowing oil to escape from the lower end of the cylinder. Thus the table is caused to move upwardly. If the handle is merely moved a certain amount upwards and then stopped, the upward movement of the table causes the pivot shaft 228 of the lever system to be moved upwardly and thereby causes the lever to be pivoted in a counter-clockwise direction about the handle shaft 236, thereby causing the valve to close and the table to become stationary in some elevated position corresponding to the displaced elevated position of the handle. If, however, the handle is moved upward in a continuous manner the table follow this movement. If the handle is moved upwardly slowly there is only a small opening of the valve cylinder ports so that oil is admitted to the upper end of th actuating cylinder and allowed to escape from the lower end relatively slowly so that the upward table movement in response to the upward handle movement is correspondingly slow. If, however, the upward movement of the handle is rapid the opening of the ports is greater and the table responds at greater speed The downward movement of the table is accomplished in a similar manner. The springs 2E6, 210 are relatively short so that their resistance to compression increases with the amount of compression. Hence the force applied to the handle is caused to increase for an increased rate of movement of the table and also for an increased resistance between the drill and the work, which drill resistance requires a greater amount of port opening to overcome. Thus the device operates like a purely mechanical sensitive drill in that the operator can feel the action of the drill through the handle. This manual operation has been described in greater detail in my above referred to co-pending application Serial No. 237,510, and need not be further described here.

In addition to purely manual operation provision is made for hydraulic operation in an automatic cycle controlled by the position of the table and modified in certain ways. The automatic cycle consists of a fast approach of the work to the drill, a slower feed movement against the drill to a predetermined depth, and a fast retraction to a neutral or stop position.

Four modified methods of operation are herein provided.

In cycle A the automatic cycle as above described is performed except that the table comes to rest when the work is close to the drill and at the end of the fast approach stroke and does not start its feed stroke until a foot pedal is operated. The cycle is initiated by depressing and holding the pedal down until the table comes to rest with the work close to the drill and the remainder of the cycle is accomplished upon release of the pedal. The subsequent depression of the pedal at any part of the stroke gives an emergency reversal of the table.

Cycle B is the automatic cycle without the intermediate stop and is started by the depression and release of the pedal. Emergency reverse-is obtained by again depressing the pedal.

In cycle C the depression and holding of the pedal in depressed position gives a continuous repeating of the automatic cycle. The release of the pedal and then the depression and subsequent release of the pedal provides for emergency return.

Cycle D is purely hand feed.

The control of the table actuating cylinder and piston in cycles A, B and C is effected through the valve I95. Thus it is necessary that this valve be provided with hydraulically operated mechanism to move the valve from a neutral poe sition into an upper position to secure upward movement of the table and into a lower position to secure downward movement of the table and also at times to hold the valve in neutral .position.

This control of the valve is obtained by a'valve holding plunger 259 and a valve setting plunger 252, located above and adapted to bear on the hub 222 of the valve lever, and a similar valve holding plunger 254 and a valve setting plunger 256 dis- .posed under and adapted to bear on the hub 222. Said pairs of plungers are opposed to each other and are located in the cylinders of bosses 258 and 268 formed in the valve housing 86, see Figs. 9, 10., 13 and 31, the cylinders for the upper pair of plungers being open at their outer ends and closed by plugs 252, 264, and the lower .cylinders being open at their lower ends and closed by the plugs 266, 258.

The valve holding plunger 253 is provided with an enlarged head 210 which engages the bottom shoulder of an enlargement of the cylinder and limits the downward movement of the plunger under influence of oil pressure in the cylinder above the head admitted through the duct 272. The lower valve holding plunger 254 is provided with a similar enlarged head 214 which limits the upward movement of the plunger under influence of oil pressure admitted under the head through the port 216.

The plunger 250 is provided with a screw 218 adjustably projected from its end and adapted to engage the hub 222 of the valve lever system. The lower plunger 254 is similarly provided with an adjustable screw 283 also adapted to engage the hub 222.

The valve setting pistons 252, 25% are provided with stems 282, 284 projected therefrom and adapted to engage the hub 222. The outer ends of the pistons are subjected to pressure oil entering their respective cylinders through ports 286, 288. The ports 272, 285 for the upper plungers 250, 252 are connected to a common duct 2%, see Fig. 31, while the ports 27%, 288 for the lower set of plungers 254, 255 are connected to a common duct 292. The outward movement of the plungers, particularly the valve positioning plungers 250, 254, is limited by engagement with their associated end caps or plugs 252, 266.

With the described arrangement, when both ducts 290, 292 are free from oil pressure, the valve springs 28-3, 2H! hold the control valve in neutral .position so that flow of oil into or out of the opposite ends of the actuating cylinder is .prevented and hence the table remains stationary. The same result occurs when both ducts 290, 292 are under oil pressure. In this event, the plungers 250, 252 and 254, 255 are forced inwardly in opposite directions against the hub 222 and since the sets of plungers have the same area hold the valve in neutral position. If, however, the duct 296 is under oil pressure and the duct 292 is free from oil pressure, as being connected to drain 14, then the plunger 252 moves downwardly and presses the hub 252 of the valve lever against the end of the lower plunger 254 which is against 7g its associated cap, thereby moving the valve and holding it in position to effect retraction of the table away from the drill. When the duct 250 is free from oil pressure and the duct 292 is under oil pressure then the piston 256 operates to move the hub and the valve upwardly and hold the hub pressed against the plunger 250, thereby setting the valve in position to effect the upward or advancing movement of the table.

The aforesaid control of the plungers is effected through means including a reversing valve 294, see Figs. 16, 17, 19v and 31, the setting of which is controlled partly by the position of the table and partly by pressure oil acting on the left hand end, Fig. 3.1, of the valve. Said reversing valve effects fast and slow advance of the table and its retraction from some advanced position to a fully retracted position.

The reversing valve 294 is of the piston type comprising four spaced and connected piston sections 2916, 298, 300, 3.02, respectively, movable axially in a cylinder bore 384 formed in a valve block 386 of an assembly of valve blocks secured by screws 308 to the side face ofthe valve housing 86, as illustrated in Fig. 3. The reversing valve has a long axial bore extended inwardly from the left hand end thereof, Fig. 19, in which is located a compression spring 3.10. bearing against an end cap 3l2 of the cylinder bore to bias the valve for movement toward the right, although not for movement independently of the controlling cam mechanism, now to. be described.

The reversing valve is provided with a stem 3M, the end of which is seated in an adjustable cup member 316, see Fig. 28, of a thrust rod 318 that is passed loosely through an opening in the rear wall of the table structure and bears in a boss 320 of an actuating arm 322 fixed on a stud 324 journalled in a block 326 fixed by suitable bolts 328 to the rear side edge part of the table structure. Said block confronts a cam carry.- ing block 330 fixed vertically to the column of the machine.

Said cam carrying block has fixed vertically adiustably thereto by bolts 332 a lower stop block 334 having an inclined cam face 336 leading to a recess 3.38 in its upper face. The position of said stop block defines the fully retracted position of the table.

The cam block 33% also has vertically adjustably secured thereto by bolts 340 a slow speed or feed cam plate 342 which is effective in setting the reversing valve for a slow or feed-rate of advance of the table. The cam block 338 also carries a second cam plate 344 also vertically adjustably secured thereto, which cam plate effects the reversing of the table.

The lever 322 is provided with a cam roll 3% which cooperates with the aforesaid cams. The lever is biased for pivotal movement in a clockwise direction or away from engagement with the cam block 330 and the cams 342, 35s by a compression spring 348 which at its lower end exerts pressure on a boss 3% of the lever and at its upper end exerts pressure on a stud 352 of the cam block 326,. In Fig. 28, the lever 322 is illustrated with the roll in engagement with the cam face 336 of the lower block 334. In this position the reversing valve is in neutral position and the table is held stationary.

To start a cycle of the machine, fluid pressure is applied against the left hand end of the reversing valve, or against the piston 296 thereof, to exert a thrust on the valve stem and to move the lever 322 in a counterclockwise direction of the machine, see Figs. 1 and 31.

against the spring 348 until the roll is in engagement with the confronting flat face of the cam block 336. This oil pressure is maintained to hold. the roll against the cam faces until the valve is moved to the right by the reversing cam at the intended end of stroke of the table or until the oil pressure is released under emergency control to effect retraction of the table. This movement of the reversing valve controls ports to effect the upward movement or advance of the table in a manner presently to be explained. Thus the cam roller 346 is caused to pass over the flat face of the cam block 338 under the slow feed cam 342. This rate of movement is relatively rapid and effects the rapid advance or traverse of the table up to close to the point of engagement between the work and the drill. The feed cam 342 is so positioned that before the drill and the work engage the roll 346 is engaged and moved to the left by the cam 342, thereby changing the setting of the reversing valve to a slow rate of advance of the table, as will presently appear. This slow rate of advance is maintained until the roll comes in contact with the reversing cam 344 whereupon the roll carrying lever 322 is moved to the left and the reversing valve is set to effect rapid retraction ofthe table. At this time there is no endwise pressure on the reversing valve so that the spring 348 is effective in maintaining the valve set in the table retraction position.

For cycles A, B and C, that is to say, all cycles except the purely hand operated cycle, the start of operation of the cycle is effected, by the depression of a foot pedal 364 located on the base The foot pedal controls a piston valve 356 located in a valve cylinder 353 having a pair of ports 368, 362 controlled by the pistons 364, 366 of the piston valve, the pistons being located on opposite sides of the ports so that the ports are in communication when the pedal is not depressed The port 362 is connected to drain by a duct 368. The end of the valve cylinder constantly receives pressure oil from a duct 318 leading to. the ports 114 of the main control valve, which ports are constantly in communication with the pressure oil line 12. Thus the duct 318 is under constant oil pressure, which pressure serves to maintain the piston valve in the normal unoperated position illustrated in Fig. 31. Depression of the foot pedal and consequent movement of the piston valve to the left causes the drain port 362 to be closed by the piston 366 and allows pressure oil to flow around the piston 364 from the duct 318 into the duct 368 and through the connecting duct 312 to the cycle selector valve.

The application of pressure oil into the duct 312 under control of the foot pedal effects the application of pressure oil into the endmost chamber 314 of the reversing valve cylinder through the intermediary of the cycle selector valve and the switching piston valves, now to be described.

There are five switching valves, see Figs. 16, l7, l8 and 31, indicated by the Roman numerals I, II, III, IV and V, the pistons of valves I, II, III and V being identical in construction, and valve IV being different. Said valves are located in cylinder bores 316, 318, 388, 382, 384,.respectively, of a valve block 386 bolted against the face of the reversing valve block 386 by the aforesaid screws 388. The valve cylinders at their upper ends are closed by the caps 388, 398, 392, 394, 386, respectively. The Valves are maintained, when not under endwise oil'pressure acting on the tops of the valves, in an upper position by compression springs 368, 488, 482, 484, 486, bearing against the lower ends of the valve and against lower end caps which have inwardly projecting studs 488 to limit the operated lower position of the valves.

The valve I has spaced pistons 418, 412 controlling ports 414, 416 so that when the valve is not depressed there is communication between the ports. The lower piston 412 also controls. a third port 418 and normally closes the port, but when the piston is depressed allows communication between the port 4 I 6 and the port 418 at which time the port 414 is closed by the upper piston 418. The bottom end part of the valve cylinder is connected freely to drain by a duct 428.

The valve II has upper and lower spaced pistons 422, 424 normally positioned to admit communication between the ports 426, 428. The piston 424 normally closes a third port 438 which is connected freely to drain by a duct 432. The valve in its lower or operated position closes the port 426 and establishes communication between the ports .428 and 438. The bottom of the cylinder is connected to drain through a restricted orifice 434 so that the valve II moves to operated position slower than the valve I which it controls and thereby permits the operation of valve I before the valve II fully operates. The valve II through port 428 controls the admission of pressure oil through a duct 436 to the top of the cylinder of valve I so that the valve I is moved down into an operated position by the application of oil pressure through the duct 436. The operation of valve I effects the movement of the reversing valve into advance position, as will presently appear.

The upper port 426 of valve II is connected to a duct 438 which receives pressure oil through the selector valve as will presently appear. Said duct is also connected with a duct 448 which admits oil under pressure to the top of the cylinder of valve II. Thus when oil under pressure flows into duct 438 valve II is caused to be operated and at the same time through ducts 426 and 428 admit pressure oil to the top of the cylinder of valve I, causing said valve to operate.

The port 416 of valve I is connected by a duct 442 to the end chamber 314 of the reversing valve. The lowermost port 418 of valve I is connected by a duct 444 with the second port 446 of the valve cylinder of valve V. Said valve V has upper and lower pistons 448 and 458 which, in the normal unoperated position of the valve, permit communication between the port 446 and the upper port 452. The upper port is in communication with a high pressure duct 454 connected with the aforesaid high pressure duct 318. The valve V is not operated during the operation of valve I and hence the supply of pressure oil for displacing the reversing valve into starting position is taken through valve IV. Valve V is caused to be operated or moved downwardly by the admission of pressure fluid to the upper end of the valve cylinder through a duct 456 which communicates with the port 414 of valve I and also with the right hand end port 458 of the reversing valve. Said port 458 is controlled by the piston 382 of the piston valve and, in the neutral position of the valve, illustrated in Fig. 31, the port 458 is connected to a drain port 468 of the reversing valve. When the valve piston 382 is in the fast advance, the drain port is sealed and the port 456 is then in communication with the adjacent port462 which is con-.-

nected through a duct 454 with the duct 292that receives oil under pressure to set the main control valve or retraction. Hence at this time valve V is caused to be operated. The lower piston 450 of valve V normally seals a lowermost valve port 468 which is connected through a duct 458 with drain. The bottom end of the valve cylinder is also connected to drain through a restricted orifree 410 so that the action is similar to the orifice 434 of valve II.

Valve IV has upper, intermediate and lower spaced pistons 412, 414, 416, respectively. The valve cylinder has ports 41B and 485 disposed between the upper and intermediate valve pistons and normally in communication. The port 418 is connected to th high pressure duct 454 while the port 485 is connected by a duct 482 with a section of the selector valve. The valve IV also has ports 484 and 48B disposed between the intermediate and lower pistons and normally in communication. The upper port 484 is connected to drain through the duct 455 and the lower port 486 is connected by a duct 458 to a section of the selector valve. The bottom end of the valve cylinder is connected freely to drain by a duct 455. The lowermost piston 415 controls a port 452 and normally seals the port. When, however, the valve is depressed by the application of pressure to the top thereof through a duct 494 leading to a section of the selector valve, said port 452 is placed in cornmunication with the port 456 and receives pressure oil which is transmitted through the duct 252 to the lower valve holding and setting plungend of the speed setting piston 88 to disable this I piston. The port 49 5 is connected through a duct 555 with a port 555 of the reversing Valve.

The reversing valve, in addition to the ports above described, has ports 5! and M2 disposed in communication between the pistons 295, 298 i of the reversing valve in the neutral position of the valve. Port 5:5 opens to a duct 514 which is "connected to selector valve sections, as will presently be described, and the port 512 communicates with the duct 25!! that is connected.

to the upper valve holding and valve setting plungers 255, The reversing valve also has a port 5H5 which is connected to a duct 5H3 leading to drain. The port is disposed between the pistons 258, 355 of the reversing valve in the neutral position of the valve and is in communication with the port 5 4'2 and consequently drains the duct 255 in the fast advance position of the reversing valve and is in communication with the port 558 and consequently drains the duct 555 in the feed position of the reversing valve. The reversing valve also has the ports 520 and 522 disposed between the ports 558 and 482 and located between valve pistons 355, 352 and in communication with each other and the port 452, in the neutral position of the valve. The ports 525, 522 are connected with a duct 524 which is also connected with the port 5i!) and leads to an orifice 525 sometimes functioning as a drain orifice and controlled by the spring opened check valve 528 opening into the end chamber 314. The valve closes against the spring pressure when said chamber is under high pressure.

The selection of the switching valves is under control of a cycle selecting valve located in a valve block 555 bolted to the outer face of the switching valve block 385 by the aforesaid bolts or screws 303. The cycle selector valve comprises a drum 532 rotatable in the cylinder bore 534 of the valve block 535. The valve has a reduced axially projecting stud shaft 555 that projects outwardly of the valve block and has fixed thereto an actuating knob 558 provided with a pointer 54!! that is rotatable in front of an arcuate series of indicia A, B, C, D, the positions of which correspond to the setting of the valve to condition the mechanism for operation in accordance with the respective cycles A, B, C, D.

The valve drum 532 is provided with three axially spaced series of passages located in the planes X, Y, Z, Fig. 23, adapted to register with corresponding passages in the valve block, the passages being spaced /2; of a, revolution or 45 apart where they occur. The drum is also provided with a series of notches 542 into which a holding ball 544, see Fig. 20, is adapted to be pressed by the spring 545 to hold the valve releasably in set position. One or more of the entrances of the passages of the first series X also function as the equivalent of the notch 542.

The valve drum 552 nearest the stud 535, or in plane X, has two ports 543 and 555 connected by axially directed internal passages 552 and 554, respectively, with correspondingly positioned ports 555, 553 located in the middle or Y series of ports, as illustrated in Figs. 24, 25 and 27a. There is also a port 555 in the first row of ports, located towards the left, Fig. 24, from the port 543 and connected by a diagonal internal passage 552 and opening into a port 554 in the second row Y of ports.

The second port row Y also has a port 556 diametrically opposite the port 555 and connected thereto by a diametrical internal passage 558. The second port row also has three peripherally consecutive ports 515, 512 and 514 connected by a passage 515. The second port row Y also has another port 518 located between the ports 558 and 554 and connected by an axially directed passage 585 with a similarly positioned port 532 in the third port row Z.

The third port row Z has four peripherally consecutive ports 554, 585, 533 and 590 connected together by a common duct 592 and located in axial line with the ports 555 and 515 and so forth, of the second port row.

The X series of ports are drain ports. The remaining series Y and Z handle pressure oil.

The valve block 555 is provided with three axially spaced sets of ports adapted to register with the three series of ports in the rotary selector valve. The block in the plane registering with the port row X of the selector value, as illustrated in Fig. 20, has a port 594 located 45 to the left of the vertical and communicating with a duct 556 that communicates with the duct 5M. There is also a port 558 disposed 45 to the right from the vertical that communicates with a duct 55!] that goes to drain.

The valve block 535, in the position registering with the second port row Y, as illustrated in Fig. 21, has a port 652 disposed on the left horizontal and a second port 554 between said port and the vertical. Said two ports are in communication with the aforesaid duct 312 that com with the aforesaid duct 438.

municates with the port 3% of the foot pedal piston valve. There is also a port 696 disposed in the upper vertical that communicates with the duct 238 that admits pressure into the top of switching valve II for operating it. 45 displaced from the port 596 is another port 608 that communicates with the duct 532 for admitting pressure to the top of switching valve III. There is also another port 6E3 that communicates There is a last port H2, 45 displaced beneath the first port 602, and said port 6&2 communicates with the duct $95 that admits pressure fluid to the top of switching valve IV for operating it.

The valve block 539, in the position corresponding to the Z row of rotary valve ports, also has a series of ports for registering with said row of rotary valve ports. These ports comprise a port GM displaced 45 to the left from the vertical, and communicating with a duct 618 that opens to the duct 5 that leads to the port 5|2 of the reversing valve. A port 6I8, 90 displaced to the right from the port 6M, communicates with a duct 432 that opens to the second port 489 of switching valve IV. 45 displaced from the port 618, in a clockwise direction, is a port 620 communicating with a duct 488 opening to the fourth port 486 of switching valve IV. 90 displaced from the port M4, in a counter-clockwise direction, is a port 622 communicating with a duct 624 that opens to the high pressure duct it-'5.

Before describing in detail the operation of the various parts of the control system, the general principles of operation of the system will be described.

For the performance of the automatic cycle in its various modifications the direction of movement of the table, and the holding stationary of the table are obtained through the main control valve I96. That is to say, the valve is shifted into one or the other of its two operated positions for fast advance or retraction or is positioned in its neutral or midposition to hold the table stationary or for the feeding of the table at the cutting rate of movement. Such movement of the table is controlled by the speed-setting or throttle valve 88, which valve is held closed except when the reversing valve is in feed position. That is to say, at the start of fast advance, the actuating cylinder receives operating oil through the main control valve. When the cams move the reversing valve to slow feed position, the main valve is moved to neutral position and the throttle valve is placed in operation and supplies the oil for advancing the table. When the reversing valve is placed in retraction position, the main valve is again operated but in the opposite direction to supply the oil for retracting the table.

The desired movements of the main valve are obtained by shifting the reversing valve from one position to the other by the cams and by operation of the foot pedal.

The reversing valve is constantly biased by its spring for movement into retraction position. In neutral position, the valve is held against movement into retracted position by the lower or neutral cam block 334. The valve is moved from neutral to fast advance position against the bias of its spring by the application of oil pressure against the end of the valve, acting in the end chamber 3'64. This pressure is first applied to start the upward movement of the table and is maintained during the fast ad- Vance and feed movements of the table to hold the valve under control of the cams. This pressure is removed by movement of the reversing valve when the valve is moved into retraction position at the end of the feed stroke.

The initial application of pressure to shift the reversing valve is initiated by the depressing of the foot pedal. Shiftingof the valve from retraction to fast advance position takes control of the pressure away from the pedal and places it under control of the valve itself except that the pressure can be removed by operation of the pedal in any part of the fast advance and feed strokes to effect retraction of the table as may be required upon drill breakage and the like.

Switching valve I effects the initial application of pressure to the reversing valve to move it from neutral to fast advance position. The operation of valve I is effected through valve II which is a control valve for valve I. Valves I and II receive pressure oil simultaneously from the pedal and hence start to operate together. Valve I operates quickly while valve II operates slowly. Thus valve I operates to admit pressure oil against the end of the reversing valve and to shift the valve from neutral before valve II has completed its operating movement. The reversing valve, upon being shifted continues the oil pressure on the end of the valve and valve II when compeltely operated releases the operating pressure on valve I so that it returns to unoperated position. A primary purpose of valve II is to permit the momentary operation of valve I.

Valve III controls the operation of the throttle valve. Said valve III is primarily under control of the reversing valve and is energized through the reversing valve when the latter is in fast advance position to disable the throttle valve and is de-energized when the reversin valve is in feed position so that the throttle valve can control the feed rate of the table.

Valves IV and V are utilized to effect emergency retraction of the table when the system is operating in accordance with one of the several cycles of operation, particularly cycle C.

The operation of the system will now be described, and Fig. 31 illustrates the setting of the selector valve for the performance of cycle A.

It will be remembered that in cycle A the foot pedal 354 is depressed to start the rapid advance of the table up to the region of engagement between the drill and the work and that the table stops when the drill is close to the work so that the operator can assure himself that everything is proper to continue the drilling operation. The releasing of the pedal from its depressed position effects the re-advance of the table, but at the slow or feed-rate. When the table has reached the desired limit of upward movement and the hole has been drilled to the required depth, the table automatically returns and stops in its lowermost or retracted position. Depression of the pedal at any part of the advancing movement of the table effects the retraction of the table to its fully retracted position and the stopping of the table in the retracted position.

In the fully retracted position, the reversing valve 294 is in neutral position, as illustrated in Fig. 31. The depression of the foot pedal 394 admits fluid from the high pressure duct 370 into the duct 3H where the pressure passes through certain of the Y series of ports in the selector valve and into ducts 438 and 582, causing the instant operation of switching valve III, the delayed operation of switching valve II, by reason of the restricted exhaust port 434 of said valve, and the instant operation of switching valve I.

The operation of valve III admits pressure oil from the duct 502 to the duct 554 for disabling the speed setting or throttle valve 88 by holding the valve closed so that no oil can get to the actuating cylinder through the duct I32 from this valve so that the oil for operating the cylinder must flow through the main valve I95. This condition is maintained so long as the pedal 354 is depressed.

The operation of switching valve I places the ports M6 and M8 thereof in communication so that pressure oil from the duct 454 can flow through valve V, which is unoperated, and duct 444 into duct 442 and thence into the end chamber 314 of the reversing valve. The building up of pressure on the end of the reversing valve moves the valve to the right and hence moves the cam roll 348 against the fast advance face of the cam block 335, as illustrated in Fig. 31a, thereby conditioning the system for fast advance or upward movement of the table.

For fast advance of the table, the main control valve I96 must be in its upper position with the high pressure port I14 in communication with the port I12 leading to the top of the actuating cylinder and with the port I75 communicating with the lower end of the cylinder opening to drain. Thus the lower valve setting plungers 254 and 256 must be under pressure and the upper plungers 25D and 252 free from pressure and hence the duct 292 must b under pressure and the duct 2% must be free from pressure.

In the neutral position of the reversing valve, however, both ducts 298, 282 are under pressure to hold the control valve I95 in neutral position. The duct 290 communicates with the port 2I2 of the reversing valve which, in turn, communicates with the port that receives pressure oil from the duct 514. The duct 252 communicates through duct 484 with the port 462 of the reversing valve. This port is in communication with a port 522 that communicates through the duct 524 with the duct 5I4. Hence both ducts 298, 292 are under pressure. The duct 5I4 receives its pressure through the communicating ducts GIG and 482 of the Z row of ports in the selector valve. The duct 482 receives pressure through the communicating ports 478 and 4.80 of valve IV, and the pressure duct 454.

When the foot pedal is depressed and the position of the reversing valve changes to fast advance, the reversing valve shifts in position to connect the duct 288 with the drain port 5I6. The duct 452, controlling the pressure to the lower plungers 254, 255, still remains in communication with high pressure through the port 522 of the reversing valve, the duct 524, the port 555, the oil flowing around the piston section 252 that at this time confronts the port and communicating with the aforesaid high pressure duct 5I4. Hence the pressure on the plungers 254, 255 forces the main valve I 95 upward to effect fast advance of the table.

The switching valves I, II and III are held down since the foot pedal remains depressed and the table advances at its fast rate of speed until the roller 345 engages and rides upon the feed m 542 and hence is displaced to the left and consequently displaces the reversing valve to the left into some position as illustrated in Filo. 311). In this position, the table movement is intended to be arrested and advance of the table is not intended to be resumed until the foot pedal 354 3 is raised. Thus the shifting of the reversing valve into feed position effects the return of the main control valve I96 to its neutral position by applying pressure to the upper valve setting plungers 250, 252.

In the feed position of the reversing valve the intermediate piston section 292 interrupts communication between the port 5I2 and the drain port 5H5 and places the port 5I2 in communication with the pressure port 5N. Thus pressure oil flows into the duct 29!] and against the plungers 258, 252 and balances the action of the lower plungers 254 and 256 so that the valve springs associated with the main valve I are effective in moving the valve into the mid or neutral position. Thus the table is stopped for movement at the beginning of the feed stroke.

The starting of the feed stroke is accomplished by removing foot pressure on the pedal and. allowing the oil pressure on the end of the pedal operated piston 354 to restore the piston to the neutral position illustrated in Fig. 21.

Upon release and consequent restoration of the piston, the control valve I95 is maintained in the neutral position in the manner just described and feed control of the table movement is obtained through the speed regulating or throttle valve 88. This is effected in the following manner. When the pedal is released and the pedal piston valve 354 returns to neutral, com munication between the high pressure duct 310 and the duct 312 is interrupted and the duct 572 is connected to drain duct 388. Thus pressure is removed from the switching valves III, II and I.

It might be stated that switching valve I was only momentarily depressed by the initial depression of the foot pedal and that valve I, after the initial operation, returned to its unoperated position. That is to say, the depression of foot pedal put operating pressure on the ends of both valves I and II. Valve I went down instantly, however, while valve II went down at a slower rate due to the restricted throttle opening 484. This slower rate of operation was sufficient to effect the operation of valve I and the shifting of the reversing valve from neutral to fast advance position. When, however, valve II was in fully operated position it connected the top of valve I with drain through the ports 428 and 430 and hence valve I returned to normal unoperated position by means of its spring.

The shifting of the operating valve from neutral to fast advance position, however, places the reversing valve port 458 in communication with the port 522, which port receives pressure oil through the duct 5I4 and through the section Z of the selector valve and unoperated switching valve IV from the high pressure duct 379. Thus the duct 458 connected with the port 458 is un der pressure and oil flows through the connected ports 4| 4 and MS of valve I in its operated position and thence to the end chamber 314 of the reversing valve maintaining the valve against the cam faces. Pressure in the duct 456 also operates on the end of the switching valve V and operates it, cutting off communication between the ports 452, 446, but for cycle A performing no other essential function. Thus the switching valve I is merely operated momentarily to initiate the setting of the reversing valve and the reversing valve maintains itself under oil pressure to maintain its cam roller in engagement with the cams.

The retraction of the foot pedal 354, as above described, effects the return of switching valve III to an unoperated position and hence takes pressure off the throttle valve 88 so that the duct I 46 communicating with the throttle valve drains through the ports 498 and 506, which are now in communication, and through the duct 566 and the communicating ports 568, I6 to drain. The throttle valve 88 can thus open under influence of its spring I 62 to the extent determined by the setting of the valve setting arm H6 and allows oil to flow through the high pressure duct 12 and the throttle valve ducts I22, I24 and through the governing valve 96 into the top of the cylinder through the duct I32. The table thus advances at a feeding rate of speed as determined by the setting of the throttle valve and at a constant rate regardless of variable thrust between the drill and the work under control of the governing valve 96.

At the end of the slow or feed traverse of the table, the cam roller 346 engages the reversing cam 344 and moves the reversing valve to the extreme left hand or retraction position illustrated in Fig. 310.

To effect retraction, the throttle valve 86 is again disabled or closed so that control of the operating fluid to and from the actuating cylinder is under control of the main valve I96 and said main valve is moved into a depressed position to allow pressure fluid to flow through the port I16 thereof and the duct I 36 into the bottom end of the cylinder and exhaust oil to flow from the top end of the cylinder through the duct I32 and the valve port I 16 to the drain 14.

To efiect depression of the valve I96, the lower valve setting plungers 254, 256 are freed from oil pressure so that they can be depressed and the upper valve setting plungers 256, 252 are put under oil pressure so that they are moved downward to depress the valve I96. Thus the duct 292 is free from pressure and the duct 296 is placed under pressure. At this time also there is no need for maintaining oil pressure in the end chamber 314 and against the end of the reversing valve and this chamber is freed from pressure by the positioning of the piston section 362 between the port 458 and the pressure port 522 and hence connecting the port 458 and the chamber 314 to drain through the port 466 and the switching valve I. The lower valve setting plungers 254, 256 are freed from pressure and connected with drain by the said piston section 362 which establishes communication between the port 362 in communication with the duct 292 and the drain port 466. The upper plungers 256, 252 are placed under oil pressure through the duct 26!] which communicates with the port 5I2 of the reversing valve and said port is in communication with the pressure port 5I6 in the retraction position of the reversing valve, as illustrated in Fig. 310.

When the table arrives in fully retracted position, the roller 346 engages the cam face 336 of the lower cam block 334 and is caused to set the valve into the neutral position illustrated in Fig. 31, thereby stopping the mechanism in fully retracted position and returning the control valve "I 96 in neutral position by placing both the upper and lower valve setting plungers 256, 252 and 254, 256 under pressure.

Emergency. retraction of the table from any advanced position thereof either in a fast ad- Vance position or a feed position is accomplished by a depression of the foot pedal 384 and through the foot pedal the movement of the reversing valve into a retraction position, as illustrated in Fig. 310. It will be remembered that in both fast advance and feed positions of the reversing valve, the reversing valve is under endwise pressure from the pressure of oil in the end chamber 314 and is held by this pressure against the counter-pressure of the spring 343. Thus the emergency depression of the foot pedal is utilized to relieve the chamber 314 from oil pressure so that the spring 348 can operate to move the reversing valve into retraction position, as illustrated in Fig. 310. g

The depression of the foot pedal operates the switching valves III, II and I as before. The valve III disables the feed control or throttle valve 88 if this valve is in use as it will be in the feed position of the reversing valve. The valve II permits the operation of the valve I. The valve I, through its ports 4I4, 4I6, which in fast advance and feed positions of the emergency valve are under oil pressure from the duct 456, controls the application of oil pressure to the duct 442 and hence to the end chamber 334. The closing of the valve cuts off communication between these ports and places the port 4 I 6 communicating with the chamber 314 in communication with the lower port MB. This port is in communication with the port 446 of valve V. Valve V is in a depressed or operated position since the duct 456 is under oil pressure and hence port 446 is in communication with port 456 which is connected to the drain duct 468. Thus the operation of the valve I connects the end chamber 314 of the reversing valve with the drain. Hence the holding pressure is removed from the emergency valve and the spring 348 is permitted to operate to move the valve into the retraction position and effect the return of the table to fully retracted and stop position.

Cycle B is essentially the same as cycle A, except that when the table is started to advance it does not come to rest with the drill and the work about in engagement, but continues its movement although at the slower or feed-rate to bring the work into engagement until the required depth of the hole is drilled, whereupon the table is retracted rapidly to its fully retracted position.

The cycle is initiated by the depression of the foot pedal as before. Thus in response to the depression of the foot pedal the table advances at a rapid rate up to the drill and then at a slower rate with the drill and work in engagement and then is retracted rapidly to separate the drill and the work and stops in a retracted position. A subsequent depression of the foot pedal causes the return or retraction of the carriage from any advanced position thereof either in a fast advance position or a feed position.

Selection of cycle B is accomplished by rotating the selector valve 532 in a counter-clockwise direction 45 from the positions illustrated in Fig. 31 to the position illustrated in Fig. 32. In this position, the high pressure duct 5 I 4 leading to the high pressure port 5I6 of the reversing valve receives high pressure oil through the duct EM and the valve ports in the Z line of passages directly from the high pressure duct 316 instead of the pressure passing through valve IV as in cycle A. The pedal operated valve, however, still maintains control of valve II through the ports 662 and 666 of the Y section of the selector valve block, which ports are respectively connected to the duct 312 leading to the pedal valve and the duct 438 leading to valve II. Valve III is thus cut out of operation as is also valve IV. Hence the only valves functioning are valves I, II and V. The cycle is started by the depression of the foot pedal as before. This causes valve II to be operated and also valve I. The operation of valve I places the chamber 314 under oil pressure and moves the reversing valve from a neutral position to a fast advance position as in Fig. 31a. It will be remembered that, in cycle A, table movement was arrested at the end of the fast approach stroke and then resumed for the feed stroke upon release of the pedal. This was done by holding valve III depressed so that when the reversing valve moved to feed position and thereby moved the control valve I96 into neutral position, the th'rottle valve 88 was also closed by pressure of oil on the end of it received through the valve III and that when the foot pedal was released and the valve III returned to neutral position the holding pressure on the throttle valve was released sothat oil could flow into the cylinder through the throttle valve to cause the cylinder and table to resume its advance at the feed-rate,

In cycle B, however, valve III is out of use and is maintained in an elevated position. Hence during the fast advance stroke the throttle valve 88 is held closed by endwise pressure of oil thereon flowing through the duct I46 and through the communicating ports 498 and 54B of the valve III and through the duct 506 and the communicating ports 508 and 520 of the reversing valve from the pressure duct 524. When the reversing valve moves from fast advance to feed position, the ports 508 and 520 are isolated from each other by the piston section 3% and the port 598 is placed in communication with the drain port 5 I 6, thereby relieving the throttle valve from holding pressure and allowing the throttle valve under action of its spring to assume a position determined by the setting of the speed arm l it. The rest of the cycle is accomplished, as has been above described in connection with cycle A.

Emergency return of the table from any advanced position thereof is accomplished by a second depression of the foot pedal. This causes the second operation of valves II and I. The operation of valve I drains pressure oil from the end chamber 314 of the reversing valve and allows the spring 348 to move the valve into retraction position, as has been explained in connection with cycle A.

Cycle C is a continuous repetition of the automatic cycle effected by depressing and holding down the pedal. Emergency return from any advanced position of the table is effected by the release, depression and release of the pedal.

The system is conditioned for cycle C operation by the rotation of the cycle selector valve a second 45 from the cycle B position or 90 from the cycle A position illustrated in Fig. 31 or into the position illustrated in Fig. 33. In this position, the high pressure duct 5|4 leading to the high pressure port 5!!! of the reversing valve receives pressure oil as before through the ducts SIB and 6M and the passages of the Z line of ports in the rotary selector valve. That is to say, the duct SIB is in communication with the port 599 of the selector valve while the duct 6 l 4 is in communication with the duct 586 of the selector valve. The duct 482, associated with the Z line of ports, is isolated. The duct 488 is connected through the port 582 and the internal passage 5% in the rotary valve with the port 518 in the Y line of ports, and through this port with the duct 438 associated with valve II. The pressure duct 312 from the pedal valve is connected through the passage 516 of the rotary valve with the duct 494 which conducts pressure fluid into the top of the switch valve IV for operating it. With this setting of the cycle selector valve, valve III is out of operation as it was in cycle B.

In starting the cycle, the pedal is depressed as before and is held depressed. This admits pressure oil through the duct 372 into the duct 494 to effect the depression of valve IV. Valve IV has a port 492 which is in communication with the ducts 292 and 464 and with the reversing valve port 452, that in the neutral position of the reversing valve, is under oil pressure. Valve IV also has a port 486 that is in communication through duct 488 and the internal passage 589 of the reversing valve with the pressure duct 438 associated with valve II. Thus depression of valve IV under pedal pressure establishes pressure communication between the reversing valve and valve II and effects the depression of valve II. Valve I receives pressure oil from valve II and hence is also depressed and at a more rapid rate as has been explained above. Valve I has a port 4l8 connected with the port 448 of valve V which is under oil pressure from a duct 494, as has been explained above. Thus depression of valve I places ports M6 and M8 in communication and allows high pressure 011 from the duct 454 to flow into the end chamber 3'54 of the reversing valve, moving this valve from neutral into fast advance position where the rest of the cycle is carried out as has been explained in connection with cycles A and B.

Automatic repetition of the cycle is accomplished by maintaining the pedal depressed be- .cause when the reversing valve is placed in neutral position at the end of the cycle conditions are restored to effect the repeated operation of valve I, as has been explained for the start of the cycle, and thus the cycle is repeated indefinitely as long as the pedal is held depressed.

Emergency retraction of the table from any advanced position thereof is obtained by the release, depression and release of the pedal. The consequence of this operation of the pedal is to relieve the end chamber 3'54 of the reversing valve from pressure. The release of the pedal in some advanced position of the table restores valve IV to an unoperated position. In this position valves I and II are free from oil pressure since the port 486 is now isolated from the pressure port 492 that receives pressure oil from the port 462 of the reversing valve in fast advance and feed positions of the valve. As a consequence, valve II returns to its unoperated position. The end chamber 3'54, however, is still under oil pressure, the pressure being transmitted through the communicating ports 454 and MS of valve I from the duct 456 and the port 458 of the reversing valve. This is true in the fast advance position but in the feed position of the valve this port is connected to drain so that endwise pressure on the reversing valve is relieved and the reversing valve is returned to retraction position by its spring. Thus, when the table happens to be in some feed position, the release of the pedal accomplishes retraction. If the table is in a fast approach position, however, the pedal valve has to be again depressed. Depression of the pedal valve again valve IV which admits pressure oil to valves I and II as before and causes their operation. The operation of valve I connects the end chamber 3'54 through port 416 of valve I with port MB of this valve. P'ort M8, however, is connected by duct 444 with port 445 of valve V. This valve is in an operated position since it is under endwise pressure through the duct 556 from the port 458 of the reversing valve, which port in the fast advance position of the valve is in communication with the pressure port 522. Thus port 446 of valve V is in communication with port 436 of the valve, which port is connected to the drain duct 463. Hence the depression of valve I in response to the depression of valve IV relieves the end chamber 374 of the reversing valve from pressure and, consequently, the reversing valve moves to retracted position to effect the retraction of the table.

In cycle D, the system is set for entire manual control by the operating handle 234 and the foot pedal is not used. The reversing valve remains in retraction position except as it may be moved into neutral position by its control cam 534 when the table is moved manually to the far end of its stroke but the reversing valve does not either in neutral or in retraction position effect any control over any parts of the system.

In setting the cycle selector valve to position for cycle D, the valve is rotated 45 in a counterclockwise position, or 135 from the cycle A position and into the position illustrated in Fig. 34. In this position the only control that is effected is the control of switching valve III which is held down and caused to apply pressure onto the end of the throttle valve 88 to hold the valve closed. Valve III and throttle valve 88 are held in such positions constantly during the time that the cycle selector valve is in cycle D position.

In the setting of the selector valve for cycle D position, pressure oil passes from the pressure duct 31!] and the duct 454 through the communicating ports 478, 480 of unoperated valve IV through the duct 482 to section Z of the selector valve and through the internal passage 589 of said valve, which passage now registers with the duct 482, and to section Y of the valve where the duct now registers with the duct 592' leading to the top of selector valve III. Pressure is constantly applied to the valve and the valve is held down in an operated position by the pressure and connects the pressure duct 562 with the duct 554 which communicates the pressure with the top of the throttle valve 88, thereby holding the throttle valve down and preventing pressure oil from passing from the duct 12 into the actuating cylinder. Thus the actuating cylinder is prevented from receiving oil except as introduced by the manual operation of the main control valve I96; and said main control valve is freed from all controlling pressure so that it can move in response to movements of the operating handle.

In cycle D, for hand operation, the rack 244 of Figs. 1 and 9, is clamped against movement in the standard 246. For the automatic cycles A, B and C, however, the rack is unclamped from the standard and so is free to move with the table.

I claim:

1. In a drilling machine, a drill, a work support, means including a hydraulic motor for effecting movement of one of the aforesaid elements relatively to the other element, a source of actuating fluid, valve mechanism operative into different settings for differently controlling the flow of fluid between said motor and source and the operation of said motor, cam mechanism controlling said valve mechanism and operative to effect predetermined changes in the setting thereof at predetermined positions of said movable having different selector settings associated with said valve mechanism and operative in difierent settings thereof to effect different manners of operation of said motor for the same setting and under control of said valve mechanism.

2. In a drilling machine, a drill, a work support, means including a hydraulic motor for effecting movement of one of the aforesaid elements relatively to the other element, a source of actuating fluid, valve mechanism controlling the flow of fluid between said motor and said source, cam mechanism controlling said valve mechanism and operative to. shift said valve mechanism into positions to secure a predetermined length of rapid advance of said moveable element from a predetermined starting position followed by a predetermined length of slower advance and a rapid retraction to the starting position, and manually controlled valve mechanism for modifying the action of said motor under control of said cam controlled valve mechanism and operative to secure the arrest of said movable element at the end of said predetermined length of rapid advance, and manually controlled valve means operative to effect the re-starting of advance of the movable element at slow speed.

3. In a drilling machine, a drill, a work support, means including a hydraulic motor for effecting movement of one of the aforesaid elements relatively to the other element, a source of actuating fluid, valve mechanism controlling the flow of fluid between said motor and said source, cam mechanism controlling said valve mechanism and operative to shift said valve mechanism into positions to secure a predetermined length of rapid advance of said movable element from a predetermined starting position followed by a predetermined length of slower advance and a rapid retraction to the starting position, manually controlled valve mechanism for modifying the action of said motor under control of said cam controlled valve mechanism and operative to secure the arrest of said movable element at the end of said predetermined length of rapid advance, and manually controlled valve means operative to effect the automatic re-advance of said movable element from its start position.

4. In a drilling machine, a drill, a work support, means including a hydraulic motor for effecting movement of one of the aforesaid elements relatively to the other element, a source of actuating fluid, valve mechanism controlling the flow of fluid between said motor and source, cam mechanism controlling said valve mechanism and operative to effect a change in the operation of said motor at predetermined positions of said movable element, and manually controlled valve means associated with said valve mechanism and operative to modify the manner of operation of said motor under control of said valve mechanism, said manually controlled valve means having means operative to secure retraction of said movable element from any advanced position thereof and to effect the arrest of said element in its fully retracted position.

5. In a drilling machine, a drill, a work support, means including a hydraulic motor for effecting movement of one of the aforesaid elements relatively to the other element, a source of actuating fluid, valve mechanism controlling the flow of fluid between said motor and said source, cam mechanism controlling said valve mechanism and operative to shift said valve mechanism into positions to secure a predeterelement, and manually controlled valve means mined length of rapid advance of said movable element from a predetermined starting position followed by a predetermined length of slower advance and a rapid retraction to the starting position, manually controlled valve mechanism for modifying the action of said motor under control of said cam controlled valve mechanism and operative to secure the arrest of said movable element at the end of said predetermined length of rapid advance, and manually controlled valve means operative to effect the restarting of advance of the movable element at slow speed, said manually controlled valve means having means operative to secure retraction of said movable element from any advanced position thereof and to effect the arrest of said element in its fully retracted position.

6. In a drilling machine, a drill, a work support, means including a. hydraulic motor for effecting movement of one of the aforesaid elements relatively to the other element, a source of actuating fluid, valve mechanism controlling the flow of fluid between said motor and said source, cam mechanism controlling said valve mechanism and operative to shift said valve mechanism into positions to secure a predetermined length of rapid advance of said movable element from a predetermined starting position followed by a predetermined length of slower advance and a rapid retraction to the starting position, manually controlled valve mechanism for modifying the action of said motor under control of said cam controlled valve mechanism and operative to secure the arrest of said movable element at the end of said predetermined length of rapid advance, and manually controlled valve means operative to efiect the automatic readvance of said movable element from its start position, said manually controlled valve means having means operative to secure retraction of said movable element from any advanced position thereof and to effect the arrest of said element in its fully retracted position.

'7. In a drilling machine, a drill, a work sup port, means including a hydraulic motor for effecting movement of one of the aforesaid elements relatively to the other element, a source of actuating fluid, valve mechanism for controlling the flow of fluid between said motor and source, cam mechanism controlling said valve mechanism and operative to effect a normal operating cycle for said movable element comprising a predetermined length of fast advance from a predetermined stop position followed by a continued advance but at a slow rate for a predetermined length and a rapid retraction to the stop position, and manually controlled selector valve mechanism operative to modify said cycle and arranged in one position to secure the stopping of the movable element at the end of the predetermined length of fast advance and operative in another position to permit the performance of the aforesaid cycle and operative in a third position to effect automatically successive repetitions of the cycle, and manually controlled valve means operative to re-start the advance of the movable element from a stationary position at the end of the fast advance range.

8. In a drilling machine, a drill, a work support, means including a hydraulic motor for effecting movement of one of the aforesaid elements relatively to the other element, a source of actuating fluid, valve mechanism for controlling the flow of fluid between said motor and source, cam mechanism controlling said valve mechanism and operative to effect a normal operating cycle for said movable element comprising a predetermined length of fast advance from a predetermined stop position followed by a continued advance but at a slow rate for a predetermined length and a rapid retraction to the stop position, manually controlled selector valve mechanism operative to modify said cycle and arranged in one position to secure the stopping of the movable element at the end of the predetermined length of fast advance and operative in another position to permit the performance of the aforesaid cycle and operative in a third position to effect automatically successive repetitions of the cycle, and manually controlled valve means operative to re-start the advance of the movable element from a stationary position at the end of the fast advance range, said manually controlled valve means also having means to secure retraction of said movable element from any advanced position.

9. In a drilling machine, a drill, a work support, means including a hydraulic motor for effecting movement of one of the aforesaid elements relatively to the other element, a source of actuating fluid, valve mechanism for controlling the flow of fluid between said motor and source, cam mechanism controlling said valve mechanism and having movement relatively thereto to position said valve mechanism to admit fluid to said motor in an amount and in a direction to secure rapid advance of said movable element for a predetermined distance and then to shift the position of said valve mechatermined distance and then further to shift the position of said valve mechanism to effect retraction of said movable element to its starting position, and manually controlled valve means operative for any setting of said valve mechanism to 40 admit fluid to said motor independently of the position of said valve mechanism with respect to said cam mechanism and in a direction to effect rapid retraction of said movable element from any advanced position thereof.

10. In a drilling machine, a drill, a Work support, means including a hydraulic motor for effecting movement of one of the aforesaid elements relatively to'the other element, a source of actuating fluid, valve mechanism for controlling the flow of fluid between said motor and source, cam mechanism controlling said valve mechanism to effect the advance of said movable element from a stop position at different rates of speed and its retraction to said stop position from a predetermined advanced position, a manually depressible valve member and valve means responsive to the release, depression and release of said depressible valve member for effecting retraction of said movable element from any advanced position thereof.

11. In a drilling machine, a drill, a work support, means including a hydraulic motor for effecting movement of one of the aforesaid elements relatively to the other element, a source of actuating fluid, valve mechanism for controlling the flow of fluid between said motor and source, cam mechanism controlling said valve mechanism to effect the advance of said movable element from a stop position at different rates of speed and its retraction to said stop position from a, predetermined advanced position, a manually depressible valve member, and valve means responsive to the depression and release of said depressible valve member for effecting retraction Of 

